Is it normal for people's personalities to change after dbs and dopaminergic medications?

Yes. Unfortunately, both dbs and sinemet (carbidopa and levodopa) or other dopaminergic meds can have changes in patient personalities. Patients can suffer from hyper-active state, vivid dreams, and even manic states from dbs/dopa meds. This is obviously only in rare patients. Consult your neurologists.
Possibly. Deep brain stimulation (dbs) or medications may result in personality changes. The procedure involves passing electrode(s) through the frontal lobes into various targets in the brain to help alleviate parkinson's symptoms. The frontal lobes are resposible for personality. Passing electrodes through older, somewhat atrophic, frontal lobes may certainly cause personality changes.